I can amplify (sorry!) / add minor corrections to Big Al's statement/s above when he wrote:

>Ralph switched back to the J45. I seem to remember a dalliance with a Zemaitis 12 string.

>Derek Brimstone played a Gibson acoustic through the 1960's and seventies. For the rest he played a Kasuge with a highly ornate carved neck. Both dreadnoughts.

>Wizz Jones played an Epiphone (Ranger model I think).

The round shouldered, 1960s Gibson J-45 (sunburst; J-50 when in natural finish), was the "working man's" grade, but great tone, Gibson flatttop of the day. Ralph McTell, John Renbourn and James Taylor (J-50) and Donovan + others (J-45) all played them and got a great sound - distinct low end "thump", silvery trebles plus a slight mid range "scoop". The Beatles also played the version with discreet added pickup (J-45E).

Gibson also introduced square shouldered models in the 60s (Country Western/Southern Jumbo/SJN - the same instrument in different finishes). As stated, Derek Brimstone had a beauty, although later he played a fancy Tama copy of a deluxe Martin Dreadnought on stage. Mike Silver had or has another. I was so impressed with the sound of these that I bought one to be like my "heroes" (no longer have it unfortunately).

Another great sounding, mid priced (for a professional grade instrument) acoustic model from the 60s was the round shouldered Epiphone Texan (not Ranger) which seemed to be a bit more readily available in the UK than its Gibson equivalent - it was built in the Gibson factory but they used the Epiphone designation (they had bought out the old Epiphone firm and had the rights to use the name) and was essentially a longer scale J-45/J-50. Again, the best of these sounded great, being the favourite guitars of (among others) Wizz Jones and Dave Burland (and Graham Nash). I would have liked one of these as well, but eventually started dabbling with Martine which took over a bit in my affections! But the best of the 60s Texans (they were a little inconsistent) still have a terrific sound.

Regarding Martins, well the trio of D-18, D-28 and (later) D-35 dreadnoughts are hard to go past, each with their own "sweet spot" for tonal quality, if you like the dreadnought sound (the smaller guitars can also sound great but lack the bigger bass of the dread, for fingerstyle and/or stage use they can be preferred by some or even many these days). I like and have owned one or 2 of each; you can find heroes who play them all, especially in American music... in the UK, Dougie Maclean, Paul Metsers and the late Isaac Guillory all played the D-35 model which also happens to coincide with my personal long term favourite playing instrument. Paul M. and Isaac G. played the 12-fret variant "D-35S" which to me is the "holy grail" of sound (considerably more full and resonant than the more "standard" 14-fret model, i.e. 14 frets clear of the body), although I have never found one for sale local enough to me (you can find them sometimes in the USA), but they are not cheap! (I contented myself with the next model down, A D-28S).

I could go on for ever but am sure that is enough for a start!!

Cheers - Tony